Table 4.

Relationship between the results of antibody tests, antigen tests, NAATs,^∗ and clinical manifestation of COVID-19.

CLINICAL MANIFESTATION	NAAT RESULT	ANTIGEN TEST RESULT	SEROLOGIC TEST RESULT		RISK OF EXPERIENCING INFECTION TRANSMISSION
			Immunoglobulin M	Immunoglobulin G
Early Stage of Infection	+	+	+	−	High
Active Phase of Infection	+	+	+	+	High
Late Stage of Infection, Possible Recurrent Infection	+	+	−	+	High
Window Period	+	+	−	−	High
Early Stage of Infection, False-Negative NAAT Result	−	+	+	−	High
Late Stage of Infection, False-Negative NAAT Result	−	+	−	+	High
Window Period, False-Negative NAAT Result	−	+	−	−	High
Asymptomatic Infection, False-Positive NAAT Result, False-Positive SerologicTest Result	+	−	+	+	Low
Window Period with Asymptomatic Infection, False-Positive NAAT Test Result	+	−	−	−	Low
Past Infection	−	−	−	+	Low
Convalescence	−	−	+	+	Low

^∗NAAT: Nucleic acid amplification test.